.TH std::span::front 3 "2024.06.10" "http://cppreference.com" "C++ Standard Libary"
.SH NAME
std::span::front \- std::span::front

.SH Synopsis
   constexpr reference front() const;  \fI(since C++20)\fP

   Returns a reference to the first element in the span.

   Calling front on an empty span results in undefined behavior.

.SH Parameters

   \fI(none)\fP

.SH Return value

   A reference to the first element.

.SH Complexity

   Constant.

.SH Notes

   For a span c, the expression c.front() is equivalent to *c.begin().

.SH Example


// Run this code

 #include <iostream>
 #include <span>

 void print(std::span<const int> const data)
 {
     for (auto offset{0U}; offset != data.size(); ++offset)
         std::cout << data.subspan(offset).front() << ' ';
     std::cout << '\\n';
 }

 int main()
 {
     constexpr int data[]{0, 1, 2, 3, 4, 5, 6};
     print({data, 4});
 }

.SH Output:

 0 1 2 3

.SH See also

   back access the last element
        \fI(public member function)\fP
